1. Field of the Invention
The present invention relates to improvements in a vehicular seat, and more particularly to a seat with a suspension unit in which a seat frame is supported by the suspension unit for absorbing vibrations and impacts applied thereto.
2. Description of the Prior Art
A variety of seats with suspension units (suspension seats) have been proposed and put into practical use. A typical suspension seat is arranged such that a seat frame is elastically supported by a parallel link mechanism and a suspension unit which are disposed between a seat cushion and a floor of an automotive vehicle. Additionally, at least a pair of extension springs are connected to the parallel link mechanism for applying upward biasing force to the suspension seat. In order to simplify the structure of the suspension seat, Japanese Utility Model Provisional Publication No. 57-20242 discloses a suspension seat in which a compression spring and a shock absorber are coaxially assembled and support a seat frame.
However, such a suspension seat has still had a limitation of a suspension stroke due to the location of the suspension unit between a suspension seat and a floor. Furthermore, when the seat cushion portion of the suspension seat vertically moves for absorbing uncomfortable shock from the vehicle body, this suspension seat tends to generate striking sound due to the collision between the parts of the suspension seat or between the part and the floor. Additionally, this collision degrades the durability of the suspension seat.